Wireless communication system, wireless communication method, and persistent computer-readable medium

Abstract

A wireless communication system, a wireless communication method, and a persistent computer-readable medium are provided. When the reception confirmation signal from the slave device (30) cannot be normally received even though the channel map is transmitted from the master device (20) to the slave device (30), and it is not determined that sharing of the channel map has been implemented, the master device (20) repeatedly transmits the channel map. However, if a determination is not made that the channel map has been shared at one time despite the number of transmissions of the channel map having reached the first predetermined number of times, the master device (20) cuts off the communication connection with the slave device (30) at a predetermined timing. As a result, it is possible to suppress the occurrence of a situation in which communication errors are continuously generated due to the difference in channel mapping between the master device (20) and the slave device (30), resulting in a decrease in communication reliability.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, a wireless communication method, and a command included in a persistent computer readable medium, in which a master device performs wireless communication with a slave device via one communication channel selected sequentially from a plurality of communication channels. Background Art

[0002] As such a wireless communication system, there is known a system described in Patent Document 1, for example. In the wireless communication system of Patent Document 1, when a data packet error occurs in a received signal of a wireless communication device, and the RSSI value of the wireless signal of the data packet is greater than a preset threshold value Th1, the wireless communication device determines that the receiving action of receiving the data packet is a reception error caused by interference with other radio waves. In addition, the wireless communication device counts the number of receptions and the number of reception errors, and stores the frequency of reception errors caused by interference in each frequency channel (number of reception errors / number of receptions). When the frequency of reception errors exceeds the threshold value Th2, the wireless communication device determines that there is an interference source in the frequency channel where the frequency of reception errors caused by interference exceeds the threshold value Th2, and stores the frequency channel as an unusable channel.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-128812 Summary of the invention

[0006] As described above, in the wireless communication system of Patent Document 1, a frequency channel whose communication quality is reduced due to interference with other radio waves is set as an unusable channel. In addition, in the wireless communication system of Patent Document 1, a frequency channel set as an unusable channel is restored to an available frequency channel after a set period has passed. Hereinafter, in this specification, such control of setting a frequency channel as an unusable channel or restoring it to an available channel is referred to as channel mapping control.

[0007] Here, the master device and the slave device constituting the wireless communication system need to have a common channel mapping. This is because the master device and the slave device have a common channel mapping, so that the same communication channel can be selected in sequence in the master device and the slave device. In addition, the channel mapping is a mapping that represents multiple communication channels that can be used in wireless communication between the master device and the slave device.

[0008] When the communication channel used for wireless communication is changed by using the above-mentioned channel mapping control, the channel mapping is also updated. Therefore, the updated channel mapping needs to be shared by the master device and the slave device together with the information indicating the start time of its use. Therefore, for example, it is considered that the master device sends the updated channel mapping and the information indicating the start time of use to the slave device based on the fact that the channel mapping is updated. However, in the case where the updated channel mapping and the information indicating the start time of use are not sent from the master device and / or received by the slave device normally, the channel mapping in the master device and the slave device may become inconsistent. In the case where the channel mapping becomes inconsistent, the communication channels used in the communication are different, which creates the possibility that communication errors occur continuously and the communication reliability is reduced.

[0009] The present disclosure has been made in view of the above-mentioned points, and an object of the present disclosure is to provide a wireless communication system, a wireless communication method, and a command provided in a persistent computer readable medium that can implement channel mapping control and suppress a decrease in communication reliability.

[0010] In order to achieve the above-mentioned object, the wireless communication system of the present disclosure is a system in which a master device performs wireless communication with a slave device via a communication channel selected sequentially from a plurality of communication channels, wherein:

[0011] The wireless communication system is configured to include:

[0012] a quality determination unit for determining the communication quality of each communication channel when the master device and the slave device are performing wireless communication;

[0013] a communication channel determination unit that determines a communication channel used for wireless communication based on a determination result of the communication quality of each communication channel by the quality determination unit;

[0014] a channel map sharing unit that transmits a channel map indicating the communication channel determined by the communication channel determination unit from the master device to the slave device so that the master device and the slave device share the channel map;

[0015] a sharing determination section that determines whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; and

[0016] a communication disconnection unit that disconnects the communication connection with the slave device in the master device,

[0017] The channel map sharing unit repeatedly transmits the channel map when the sharing determination unit does not determine that the sharing of the channel map is achieved despite the transmission of the channel map.

[0018] The communication disconnection unit disconnects the communication connection with the slave device at a predetermined timing based on the fact that the sharing determination unit has never determined that the channel map is shared even though the channel map sharing unit has transmitted the channel map a first predetermined number of times.

[0019] In addition, the wireless communication method of the present disclosure is a method in which a master device performs wireless communication with a slave device via one communication channel sequentially selected from a plurality of communication channels, wherein:

[0020] The wireless communication method is constituted to include:

[0021] a quality determination step of determining the communication quality of each communication channel when the master device and the slave device are performing wireless communication;

[0022] a communication channel determination step of determining a communication channel used for wireless communication based on the determination result of the communication quality of each communication channel in the quality determination step;

[0023] a channel map sharing step of sending a channel map representing the communication channel determined in the communication channel determination step from the master device to the slave device so that the master device and the slave device share the channel map;

[0024] a sharing determination step of determining whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; and

[0025] The communication disconnection step is to disconnect the communication connection between the master device and the slave device.

[0026] In the channel map sharing step, when the channel map is transmitted but it is not determined in the sharing determination step that the channel map is shared, the transmission of the channel map is repeated.

[0027] In the communication disconnection step, the communication connection with the slave device is disconnected at a predetermined timing based on the fact that the channel map is not determined to be shared in the sharing determination step even though the number of times the channel map is transmitted reaches a first predetermined number in the channel map sharing step.

[0028] In addition, the persistent computer-readable medium of the present disclosure is a persistent computer-readable medium having a command executed by at least one processor, wherein the command is used for the master device to perform wireless communication with the slave device via a communication channel selected sequentially from a plurality of communication channels, and when the command is executed, the at least one processor is caused to implement:

[0029] A quality determination function for determining the communication quality of each communication channel when the master device and the slave device are communicating wirelessly;

[0030] a communication channel determination function that determines a communication channel used for wireless communication based on a determination result of the communication quality of each communication channel obtained by the quality determination function;

[0031] a channel map sharing function that transmits a channel map representing a communication channel determined by the communication channel determination function from the master device to the slave device so that the master device and the slave device share the channel map;

[0032] a sharing determination function that determines whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in accordance with the reception of the channel map; and

[0033] A communication disconnection function, which disconnects the communication connection between the master device and the slave device.

[0034] When the channel map is transmitted by the channel map sharing function but the sharing determination function does not determine that the channel map is shared, the transmission of the channel map is repeated.

[0035] The communication disconnection function disconnects the communication connection with the slave device at a predetermined timing based on the fact that the sharing determination function has never determined that the channel map is shared even though the channel map sharing function has transmitted the channel map a first predetermined number of times.

[0036] As described above, in the commands provided by the wireless communication system, wireless communication method, and persistent computer-readable medium of the present disclosure, when the channel mapping is sent but it is not determined that the sharing of the channel mapping has been achieved, the channel mapping is repeatedly sent. Thus, the possibility that the master device and the slave device can share the channel mapping can be increased. However, when the channel mapping is sent a first predetermined number of times but no determination is made that the channel mapping has been shared, the communication connection with the slave device is cut off at a predetermined timing. Thus, the occurrence of a situation in which communication errors are continuously generated due to the difference in channel mapping between the master device and the slave device, resulting in a reduction in communication reliability, can be suppressed.

[0037] The reference signs in the above parentheses are merely signs showing an example of the correspondence relationship with the specific configurations in the embodiments described later in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure at all.

[0038] In addition, technical features described in each of the claims other than the features of the present disclosure described above will become clear from the description of the embodiments described later and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a block diagram showing a schematic configuration of a wireless communication system according to the first embodiment.

[0040] Figure 2 This is a diagram showing an example of the electric field intensity distribution in the communication environment between the master device and the slave device.

[0041] Figure 3 This is a diagram showing an example of the received signal strength of each communication channel.

[0042] Figure 4 This is a flowchart showing an example of a connection sequence between the master device and the slave device in the first embodiment.

[0043] Figure 5 This is a flowchart showing an example of a communication sequence between the master device and the slave device in the first embodiment.

[0044] Figure 6 This is a flowchart showing an example of the channel mapping sharing process according to the first embodiment.

[0045] Figure 7 This is a timing chart for explaining a control example performed by the channel mapping sharing process according to the first embodiment.

[0046] Figure 8 This is a flowchart showing an example of the channel mapping sharing process according to the second embodiment.

[0047] Fig. 9 This is a timing chart for explaining a control example performed by the channel mapping sharing process according to the second embodiment.

[0048] Fig.10 This is a flowchart showing an example of a communication sequence between the master device and the slave device in the second embodiment.

[0049] Fig.11 This is a flowchart showing an example of a communication sequence between a master device and a slave device in a modified example. DETAILED DESCRIPTION

[0050] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, for identical or similar structures, descriptions are sometimes omitted by marking the same reference numerals throughout a plurality of drawings. In the case where only a portion of a structure is described in each embodiment, the other portions of the structure can be applied to the structures of other embodiments previously described. In addition, not only the combinations of structures explicitly described in the description of each embodiment, but also the structures of a plurality of embodiments may be partially combined with each other even if not explicitly described, as long as the combination does not particularly cause obstacles.

[0051] (First Embodiment)

[0052] The wireless communication system of this embodiment includes at least one master device and at least one slave device. At least one of the master device and the slave device can be mounted on a mobile object for use. The mobile object includes, for example, vehicles such as automobiles and railway vehicles, flying objects such as electric vertical take-off and landing aircraft and drones, ships, construction machinery, agricultural machinery, etc.

[0053] As a specific application in a vehicle, the wireless communication system of this embodiment can be applied to a battery management system for managing batteries mounted as battery packs in electric vehicles such as electric vehicles, hybrid vehicles, and plug-in hybrid vehicles. When applied to a battery management system, for example, a master device is connected to a battery control device, and a plurality of slave devices are respectively connected to monitoring devices provided on a plurality of battery stacks constituting the battery pack. In this case, the master device and the plurality of slave devices are all mounted on the vehicle.

[0054] Each monitoring device provided for each of the plurality of battery stacks uses various sensors to obtain battery information such as the voltage and current of each battery cell contained in the corresponding battery stack, the temperature of the battery stack, etc. In addition, when each monitoring device receives data requesting battery information from the battery control device via the wireless communication system, it sends the obtained battery information to the battery control device via the wireless communication system. Based on the obtained battery information, the battery control device calculates the charge capacity (SOC) of the entire battery stack, drives the heating / cooling mechanism to adjust the temperature of the battery pack to an appropriate range, and determines whether it is necessary to perform the so-called equalization process to make the voltage of each battery cell consistent. When the battery control device determines that the equalization process needs to be performed in at least one battery stack, it instructs the corresponding monitoring device to perform the equalization process via the wireless communication system. In addition, each monitoring device performs a process for determining the abnormality of various sensors and the abnormality of its own operation, and when an abnormality is determined, it sends abnormal information to the battery control device via the wireless communication system.

[0055] Alternatively, the wireless communication system of this embodiment can also be applied to a so-called smart key system or a tire pressure monitoring system in a vehicle. When applied to a smart key system, for example, a master device is mounted on a vehicle and connected to a control device for controlling the locking and unlocking of vehicle doors, and the starting and shutting down of a driving source such as an engine of the vehicle. At least one slave device is mounted on a mobile key or a portable terminal owned by at least one user. When applied to a tire pressure monitoring system, a master device is mounted on a vehicle and connected to a control device for displaying tire pressure, issuing warnings in the event of abnormal air pressure, and the like. Multiple slave devices are disposed in each tire and connected to an air pressure detection device that is also disposed in each tire.

[0056] Furthermore, the wireless communication system of this embodiment can also be applied to a vehicle diagnostic system. In this case, for example, multiple slave devices are connected to multiple vehicle-mounted equipment with self-diagnosis functions, and the master device is connected to a diagnostic control device installed in a service plant. In the above example, the master device and at least one of the multiple slave devices are arranged at a fixed position, and / or the master device and at least one of the multiple slave devices are mounted on the vehicle.

[0057] However, the application examples of the wireless communication system of this embodiment are not limited to vehicles, and as mentioned above, it can also be applied to systems that control and manage various equipment such as mobile objects other than vehicles, such as flying objects such as drones, ships, construction machinery, agricultural machinery, etc. Furthermore, the wireless communication system of this embodiment can also be applied to systems that control and manage various equipment in buildings such as buildings, production equipment such as factories, etc.

[0058] Figure 1 : is a block diagram showing a simplified structure of a wireless communication system 10. The master device 20 and the slave device 30 of the wireless communication system 10 are both mounted on, for example, a vehicle (car). At this time, the master device 20 and the slave device 30 may be configured as a structure arranged in a common frame, or may be configured as a structure not arranged in a common frame. The master device 20 may be one or more. In the case of providing multiple master devices 20, the multiple master devices 20 may respectively communicate with at least one slave device 30 belonging to different groups, and the multiple master devices 20 may also communicate with at least one slave device 30 belonging to the same group. The master device 20 and the slave device 30 perform wireless communication via a communication channel selected sequentially from multiple communication channels, for example, in a Bluetooth Low Energy (Bluetooth is a registered trademark, hereinafter referred to as Bluetooth LE) communication manner.

[0059] As an example, the wireless communication system 10 of this embodiment includes a master device 20 and a plurality of slave devices 30. Figure 1 In the figure, only one slave device 30 is shown for simplicity of illustration, but a plurality of slave devices 30 can be configured in the same manner.

[0060] In the wireless communication between the master device 20 and the slave device 30, frequency bands used in short-range communication, such as the 2.4 GHz band and the 5 GHz band, can be used. Compared with the radio waves in the LF band, radio waves in such high-frequency bands have the property of being more straight-traveling and being easily reflected by metal objects such as the body of a vehicle. LF is the abbreviation of Low Frequency. As standards for short-range communication, for example, Bluetooth, Bluetooth LE, etc. can be used. As an example, the master device 20 and the slave device 30 of the present embodiment are configured to be able to implement wireless communication in accordance with the Bluetooth LE standard (hereinafter referred to as Bluetooth LE communication). The details of the communication method involving communication connection and encrypted communication are implemented according to the timing specified by the Bluetooth LE standard.

[0061] The main device 20 is as follows Figure 1 The master device 20 is shown as having a control circuit (CNT) 21, a wireless communication circuit (WC) 22, and an antenna 23. In addition to the above elements, the master device 20 also has an input / output interface and a bus for communicating with devices other than the slave device 30 by wire or wireless. In addition, the processing such as the channel mapping control processing, the channel mapping production processing, and the channel mapping sharing processing described later can be implemented by the control circuit 21, or part or all of these processing can be implemented by other control devices provided outside the master device 20.

[0062] The control circuit 21 is, for example, a computer including a processor 211 and a memory 212. The memory 212 includes, for example, a RAM and a ROM. RAM is an abbreviation of Random Access Memory, and ROM is an abbreviation of Read Only Memory.

[0063] In the control circuit 21, the processor 211 uses the RAM as a temporary storage area and executes the program stored in the ROM, thereby performing the specified processing (control). The processor 211 constructs multiple functional units by executing multiple commands contained in the program. There can also be multiple processors 211. The storage medium of the program is not limited to ROM. For example, various storage media such as HDD and SSD can be used. HDD is the abbreviation of Hard-disk Drive. SSD is the abbreviation of Solid State Drive.

[0064] The processor 211 is, for example, a CPU, an MPU, a GPU, a DFP, etc. CPU is the abbreviation of Central Processing Unit. MPU is the abbreviation of Micro-Processing Unit. GPU is the abbreviation of Graphics Processing Unit. DFP is the abbreviation of Data Flow Processor. The control circuit 21 can be implemented by combining multiple types of computing processing devices such as CPU, MPU, GPU, etc. Alternatively, the control circuit 21 can also be implemented as a SoC. SoC is the abbreviation of System on Chip. The control circuit 21 can be implemented using ASIC or FPGA. ASIC is the abbreviation of Application Specific Integrated Circuit. FPGA is the abbreviation of Field-Programmable Gate Array.

[0065] The control circuit 21 generates a command to request processing from the slave device 30 (e.g., a command to request data, a command to request execution of a predetermined process, etc.), and transmits the transmission data including the command to the wireless communication circuit 22 using a transmission data packet. In addition, the control circuit 21 receives the data packet transmitted from the slave device 30 via the wireless communication circuit 22, and executes a predetermined process based on the data included in the received data packet. That is, the wireless communication performed between the master device 20 and the slave device 30 is data packet communication.

[0066] The wireless communication circuit 22 includes an RF circuit (not shown) for wirelessly transmitting and receiving data packets. The wireless communication circuit 22 has a transmission function of modulating a transmission signal and oscillating it at the frequency of an RF signal. The wireless communication circuit 22 has a reception function of demodulating a reception signal. RF is the abbreviation of radio frequency.

[0067] The wireless communication circuit 22 modulates the data packet containing data sent from the control circuit 21 and sends it to the slave device 30 via the antenna 23. The control circuit 21 outputs the data obtained by encrypting the transmission data such as the battery information request data using the encryption information exchanged in the connection establishment process described later to the wireless communication circuit 22. The wireless communication circuit 22 assigns the data required for wireless communication such as communication control information to the transmission data packet and sends it. The data required for wireless communication includes, for example, an identifier (ID), a sequence number, a next sequence number, an error detection code, etc. The wireless communication circuit 22 can also control the data size, communication format, scheduling, error detection, etc. of the communication between the master device 20 and the slave device 30. The above-mentioned control related to communication can also be performed by the control circuit 21.

[0068] The wireless communication circuit 22 receives and demodulates the data packet transmitted from the device 30 via the antenna 23. Then, the demodulated data packet is transmitted to the control circuit 21. The antenna 23 converts the electrical signal into a radio wave and radiates it into space. The antenna 23 receives the radio wave propagating in space and converts it into an electrical signal.

[0069] like Figure 1 As shown, the slave device 30 includes a control circuit (CNT) 31, a wireless communication circuit (WC) 32, and an antenna 33. In addition to the above elements, the slave device 30 also includes an input / output interface and a bus for communicating with devices other than the master device 20 by wire or wireless. The control circuit 31 has the same structure as the control circuit 21 of the master device 20. The control circuit 31 includes, for example, a processor 311 and a memory 312. The memory 312 includes, for example, a RAM and a ROM.

[0070] The control circuit 31 performs the requested processing (response processing such as obtaining the requested data and returning it, execution processing of the requested processing, etc.) based on the request instruction obtained via the wireless communication circuit 32. For example, in the case where the request instruction contained in the received data is a request to send battery information, the control circuit 31 of the slave device 30 sends the sending request to the corresponding battery stack monitoring device to obtain the battery information from the monitoring device. In addition, the control circuit 31 sends the data encrypted using encryption information containing the processing result (such as the obtained battery information) to the wireless communication circuit 32 as a response to the request. The control circuit 31 can also perform, for example, control of a device mounted on a vehicle according to the requested processing.

[0071] The wireless communication circuit 32 includes an RF circuit (not shown) for wirelessly transmitting and receiving data packets. The wireless communication circuit 32 has a transmitting function and a receiving function similar to the wireless communication circuit 22. The wireless communication circuit 32 receives a data packet transmitted from the host device 20 via the antenna 33 and demodulates the data packet. And, the data contained in the demodulated data packet is transmitted to the control circuit 31. The wireless communication circuit 32 modulates the data packet containing data transmitted from the control circuit 31 and transmits it to the host device 20 via the antenna 33. The wireless communication circuit 32 adds data required for wireless communication such as communication control information to the transmission data packet and transmits it.

[0072] The wireless communication circuit 32 may also control the data size, communication format, scheduling, error detection, etc. of the communication between the master device 20 and the slave device 30. The above-mentioned control related to communication may also be performed by the control circuit 31. The antenna 33 converts the electrical signal into an electric wave and radiates it into space. The antenna 33 receives the electric wave propagating in the space and converts it into an electrical signal.

[0073] Figure 2 This is a diagram showing an example of the electric field intensity distribution in the communication environment between the master device 20 and the slave device 30 . Figure 2 The electromagnetic field simulation results at a predetermined timing at a predetermined frequency are shown. Hereinafter, the electric field intensity distribution may be expressed as the electric field distribution.

[0074] The master device 20 and the slave device 30 are, for example, arranged at specified positions in a vehicle. When radio wave signals of a specified frequency are transmitted from the master device 20 and the slave device 30 respectively arranged at specified positions, portions with high and low electric field strengths are generated in the use environment due to interference between the transmitted waves and reflected waves or interference with external noise. The reflected waves are generated by reflections from metal elements of the vehicle existing around the master device 20 and the slave device 30, such as reflections from the vehicle body, reflections from metal frames, reflections from wiring harnesses, and the like. For this reason, multiple Figure 2 The portion with strong electric field intensity and the portion with weak electric field intensity as shown are so-called NULL points.

[0075] If slave device 30 is located in or near a portion of the electric field with weak electric field strength in the electric field distribution between slave device 30 and master device 20, slave device 30 is more likely to fail to correctly receive the wireless signal from master device 20, resulting in a communication error. A communication channel with a high probability of such a communication error is a communication channel with reduced communication quality.

[0076] Here, when the master device 20 and the slave device 30 perform wireless communication via a communication channel selected sequentially from a plurality of communication channels, since the frequencies of the communication channels are different, the electric field distribution of the communication channels also changes. As a result, the communication quality in each communication channel will be different.

[0077] For example, Figure 3 As shown, in the wireless communication performed via the communication channel A, the received power (received signal strength), which is one of the parameters indicating the communication quality, is good. In addition, in the wireless communication performed via the communication channel C, the received power shows a very high value. Therefore, when the master device 20 and the slave device 30 use the communication channels A and C with good or very high communication quality, high-quality wireless communication with communication errors sufficiently suppressed can be performed. On the other hand, in the wireless communication performed via the communication channels B and N, the received power is reduced. Therefore, when the master device 20 and the slave device 30 use the communication channels B and N with reduced communication quality, the possibility of communication errors occurring in the wireless communication becomes high. In addition, in Figure 3 In FIG. 1 , for easy understanding, an example of received signal strength relative to frequency is shown by a solid line.

[0078] Therefore, it is preferable that the wireless communication between the master device 20 and the slave device 30 be performed using a communication channel that enables high-quality wireless communication, avoiding a communication channel with reduced communication quality.

[0079] However, the electric field distribution between the master device 20 and the slave device 30 changes according to the external environment (noise from the outside, etc.), the vibration of the master device 20 and / or the slave device 30 (including the vibration of the wiring harness), etc. Therefore, when the master device 20 and the slave device 30 are mounted on the vehicle, the electric field distribution of the communication environment of the master device 20 and the slave device 30 changes according to, for example, the state of the vehicle (e.g., driving or stopping), the state of the surrounding environment of the vehicle (e.g., more or less external noise), etc. As a result, the communication channel with good communication quality and the communication channel with reduced communication quality are not fixed, and there is a possibility of changing at all times. Therefore, it is required to delete the corresponding communication channel from the multiple communication channels used for wireless communication according to the situation that the communication quality is reduced, and to restore the corresponding communication channel to one of the multiple communication channels used for wireless communication according to the situation that the communication quality is restored.

[0080] In the wireless communication system 10 of the present embodiment, as a plurality of communication channels for wireless communication, a control process for realizing wireless communication between the master device 20 and the slave device 30 by removing a communication channel with reduced communication quality and using a communication channel with a certain communication quality is described with reference to FIG. Figure 5 The communication sequence between the master device 20 and the slave device 30 is described with reference to FIG. Figure 5 In FIG. 1 , the master device 20 is represented as MASTER (master device), and the slave device 30 is represented as SLAVE (slave device). Figure 5 FIG. 2 shows a communication sequence performed between the master device 20 and one slave device 30. The master device 20 and the plurality of slave devices 30 independently implement Figure 5 The communication timing is shown.

[0081] Here, the master device 20 and the slave device 30 execute Figure 5 Prior to the communication sequence shown, a connection establishment process is performed. Figure 4 , a connection sequence including a connection establishment process from the start-up of the master device 20 and the slave device 30 until data communication is performed is shown. For example, when the wireless communication system 10 is mounted on a vehicle, if the IG signal is switched from disconnected to connected due to a user's operation, the connection sequence starts. In addition, when the master device 20 and the slave device 30 are always connected, the connection sequence is implemented only once at a predetermined timing. However, when an error occurs during communication and the wireless communication connection between the master device 20 and the slave device 30 is disconnected, the connection sequence is sometimes implemented in order to reconnect.

[0082] When the connection sequence starts, the master device 20 and the slave device 30 respectively perform initialization processing to initialize various variables, timers, etc. in steps S10 and S110. After that, the master device 20 and the slave device 30 respectively perform connection establishment processing in steps S20 and S120. The connection establishment processing is performed between the master device 20 and all the slave devices 30 when there are multiple slave devices 30 as the connection object of the wireless communication with the master device 20. In the connection establishment processing, for example, the slave device 30 performs a broadcast action to send a broadcast signal via a communication channel for broadcasting, and the master device 20 performs a scanning action to scan the broadcast signal. The communication channel for broadcasting includes multiple (for example, three in the case of Bluetooth LE) communication channels. When the master device 20 receives a broadcast signal in any communication channel through a scanning action, it sends a connection request to the slave device 30 that sent the broadcast signal. Thus, a communication connection is established between the master device 20 and the slave device 30. When the master device 20 and the slave device 30 determine that the communication connection is established in steps S30 and S130 , respectively, the master device 20 proceeds to step S40 , and the slave device 30 proceeds to step S140 .

[0083] The master device 20 and the slave device 30 perform the exchange of connection information in steps S40 and S140, respectively. In the exchange of the connection information, the master device 20 and the slave device 30 exchange encryption information for data communication and share the initial information related to frequency channel hopping. The initial information includes, for example, channel mapping, frequency hopping mode or function for frequency hopping.

[0084] Next, the master device 20 and the slave device 30 perform data communication via the communication channel for data selected sequentially from the plurality of communication channels in accordance with each communication event generated periodically in steps S50 and S150, respectively. Figure 5 In addition, when a plurality of slave devices 30 are provided, the master device 20 assigns communication periods (sub-events) to the plurality of slave devices 30 in each communication event, thereby sequentially communicating with the plurality of slave devices 30.

[0085] When the master device 20 and the slave device 30 determine that the communication connection is disconnected in steps S60 and S160, respectively, the Figure 4 The connection timing shown. For example, when the wireless communication system 10 is mounted on a vehicle, the master device 20 and the slave device 30 sometimes determine that the communication connection is disconnected if the IG signal is switched from on to off due to a user's operation. In other cases, when the master device 20 and the slave device 30 cannot normally implement data communication for a predetermined number of consecutive times (equivalent to the third predetermined number of times in the claims), the communication connection is determined to be disconnected. Furthermore, in the present embodiment, as described later, when the master device 20 determines that the new channel mapping cannot be shared with the slave device 30 during the channel mapping update period (channel mapping update period), the master device 20 determines that the communication connection is disconnected.

[0086] Next, refer to Figure 5 The flowchart of the data communication is used to illustrate the communication sequence of data communication. Figure 5 As shown, the master device 20 sends a request instruction such as data to the slave device 30 in step S210, that is, sends a data request. However, in addition to the data request, the master device 20 can also send a request such as executing a prescribed process. When the slave device 30 receives the data request in step S310, it performs a checksum determination based on the error detection code contained in the received data request in step S320 to confirm whether the data request is correctly received. In the case where the slave device 30 determines that the data request is not correctly received based on the checksum determination result in the process of step S320, for example, in step S330, it sends a signal indicating that the data request is not correctly received or a signal requesting to send the data request again. On the other hand, in the case where the slave device 30 determines that the data request is correctly received in the process of step S320, in step S330, it performs a prescribed process required for the response, such as a process of obtaining the requested data and sending it.

[0087] In addition, the master device 20 and the slave device 30 perform frequency channel hopping for each communication event to switch the communication channel for data to be used, thereby transmitting and receiving data requests and requested data. At this time, the master device 20 and the slave device 30 determine the communication channel to be switched by frequency channel hopping according to the channel mapping they each have. In addition, in the case of Bluetooth LE communication, 37 communication channels are prepared as communication channels for data.

[0088] The master device 20 receives the requested data in step S220. And, in step S230, the master device 20 performs, for example, a checksum determination based on the error detection code included in the received data to confirm whether the data is correctly received. In the following step S240, if the master device 20 determines that the data is not correctly received in the process of step S230, or if the self device 30 receives a signal indicating that the data request is not correctly received, it determines whether to perform the retransmission process within the same communication event. For example, the master device 20 can be designed to determine to retransmit if there is a margin to the extent of retransmission before the end time of this communication event (sub-event), and to determine not to retransmit if there is no margin. In step S240, if the master device 20 determines to retransmit, it executes the process from step S210 again. If it is determined that the data is not correctly received in the process of step S230 or if it is determined not to retransmit in step S240, the master device 20 enters the process of step S250.

[0089] In step S250, the host device 20 performs processing based on the information included in the received data. In addition, if it is determined in the process of step S230 that the data is not correctly received or a signal indicating that the data request is not correctly received is received from the self-device 30, and it is determined in the process of step S240 not to resend, the process of step S250 may be omitted or the process of step S250 may be performed based on the previously received data.

[0090] In step S260, the master device 20 detects the received signal strength (RSSI) and the packet error rate (PER) as characteristic data indicating the communication quality of the signal received from the slave device 30. RSSI is an indicator indicating the strength of the signal sent from the slave device 30 and received by the master device 20. PER expresses the ratio of the number of error data packets to the number of received data packets of the master device 20 as a percentage. The master device 20 may also detect the signal-to-noise ratio (SNR) / signal-to-interference-and-noise ratio (SINR) instead of RSSI. SNR / SINR can be detected, for example, based on the ratio of the RSSI value when the master device 20 receives a wireless signal from the slave device 30 to the RSSI value when no wireless signal is received. In addition, the master device 20 may also detect the bit error rate (BER) or the packet arrival rate (PAR) instead of PER. The master device 20 saves and accumulates the detected RSSI or SNR / SINR and PER, BER or PAR for each communication channel. In addition, characteristic data representing communication quality can be acquired by slave device 30 detecting RSSI, PER, etc. when receiving a signal from master device 20 and sending them to master device 20, in addition to or instead of detection by master device 20 as described above.

[0091] In step S270, the master device 20 determines whether the communication quality of the communication channel used in the wireless communication with the slave device 30 has been reduced based on the characteristic data indicating the communication quality of the communication channel detected in step S260. Furthermore, the master device 20 deletes the communication channel determined to have reduced communication quality from the communication channels used for the wireless communication between the master device 20 and the slave device 30. In addition, the deleted communication channel is a communication channel for data. For example, an example of a condition for determining whether the communication quality has been reduced is that the RSSI is compared with a threshold value for RSSI and the PER is compared with a threshold value for PER, and the result is that at least one of the RSSI and the PER does not meet the threshold value. In addition, the parameter compared with the threshold value may be one. In addition, the parameter compared with the threshold value may be the parameter just before detected in step S260, or may be a value obtained by averaging a predetermined number of parameters detected in a plurality of past wireless communications related to the same communication channel or a median value thereof.

[0092] In step S280, the master device 20 performs a recovery determination of the communication channel that has been deleted according to the deletion determination at the time of the communication event so far. In the recovery determination, if the prescribed recovery condition is satisfied, the deleted communication channel is restored as a communication channel for wireless communication. For example, as an example of the prescribed recovery condition, it can be set to restore the deleted communication channel according to the fact that a prescribed time has passed since the deletion of the communication channel. Or, as another example of the prescribed recovery condition, it can also be set to restore the deleted communication channel to a communication channel for wireless communication according to the fact that the communication channel adjacent to the deleted communication channel shows good communication quality. In this way, the communication channel that is determined to be recoverable as a communication channel for wireless communication is incorporated into the channel mapping and is actually used in the wireless communication between the master device 20 and the slave device 30. The deletion determination process of step S270 and the recovery determination process of step S280 are equivalent to the channel mapping control process in the present disclosure. In addition, if the communication quality of the communication channel that has been restored is still reduced when it is actually used for wireless communication, it will become the object of deletion again according to the deletion determination.

[0093] In step S290, the master device 20 performs channel mapping production processing based on the deletion determination result of step S270 and the restoration determination result of step S280. In the present embodiment, independent channel mappings are produced for a plurality of slave devices 30. However, a common channel mapping may also be produced for a plurality of slave devices 30. In the case of producing a common channel mapping, an AND operation (AND operation) of the communication channels included in the channel mapping of each slave device 30 is performed to extract a plurality of communication channels common to each channel mapping.

[0094] In addition, the channel map may indicate a communication channel that can be used in wireless communication, or may indicate an unusable communication channel. Furthermore, both the usable communication channel and the unusable communication channel may be indicated. In addition, when the usable / unusable communication channel is changed due to the production of the channel map, the frequency channel hopping pattern may also be updated. When the frequency channel hopping pattern is not updated and the communication channel scheduled for frequency hopping is unusable, for example, the next communication channel scheduled for frequency hopping may be used.

[0095] In step S300, the master device 20 executes a process for sharing the channel map created by the channel map creation process in step S290 with the slave device 30. This channel map sharing process will be described in detail later.

[0096] Here, the deletion determination process and the restoration determination process described above can be implemented each time the master device 20 and the slave device 30 communicate with each other. Alternatively, the deletion determination process and the restoration determination process can also be matched with the channel mapping update cycle described later and implemented together each time the master device 20 and the slave device 30 communicate multiple times. In this case, each time the master device 20 and the slave device 30 communicate, in step S260, characteristic data indicating the communication quality of the communication channel used for communication is detected and accumulated. And, based on the accumulated characteristic data, the deletion determination of step S270 and the restoration determination of step S280 are uniformly implemented. Similarly, the channel mapping production process of step S290 can also be implemented each time the master device 20 and the slave device 30 communicate with each other. Alternatively, the channel mapping production process can also be matched with the channel mapping update cycle described later and implemented each time the master device 20 and the slave device 30 communicate multiple times.

[0097] Next, refer to Figure 6 The flowchart of illustrates the above-mentioned channel mapping sharing process. Figure 6 The flowchart of FIG. 1 shows an example of channel mapping sharing processing.

[0098] In this embodiment, if Figure 7 As shown in the timing diagram, the channel mapping shared by the master device 20 and the slave device 30 is updated every multiple communication events (six communication events in the example shown in the figure). That is, the period of multiple communication events is the applicable period of the channel mapping and becomes the channel mapping update period. In this way, by periodically updating the channel mapping, the master device 20 and the slave device 30 can use the channel mapping that matches the changes in the communication quality of each communication channel to perform high-quality communication. However, the update of the channel mapping can also be implemented irregularly, for example, on the condition that the channel mapping has been updated. That is, the channel mapping can be updated on the condition that the communication channels included in the channel mapping have changed as a result of the deletion determination process and the recovery determination process. In addition, as Figure 7 As shown, in each communication event, the master device 20 is configured to perform one communication in a sub-event allocated to each slave device 30 .

[0099] like Figure 7 As shown in the timing diagram of , during the applicable period of the current channel mapping, the sharing process of the new channel mapping is started. That is, based on the multiple characteristic data indicating the communication quality detected before the applicable period of the current channel mapping, the new channel mapping is created by the channel mapping creation process and is determined as the new channel mapping. Further, based on the multiple characteristic data indicating the communication quality detected based on the communication between the master device 20 and the slave device 30 during the applicable period of the current channel mapping, the next new channel mapping is created and is determined as the next new channel mapping before the applicable period of the new channel mapping.

[0100] Figure 6 Flowchart of the channel mapping sharing process for Figure 7 Each channel map update cycle shown in the timing diagram of FIG. 5 makes the master device 20 and the slave device 30 share a new channel map. In the first step S510, the master device 20 determines whether the value of the map sharing counter has become zero, indicating that the sharing of the channel map between the master device 20 and the slave device 30 has been successful. In addition, the map sharing counter is initially set to a value other than zero at the time point when the channel map update cycle starts.

[0101] If the value of the mapping sharing counter is zero, that is, the sharing of the new channel mapping in the master device 20 and the slave device 30 has been successful, it is no longer necessary to send the new channel mapping from the master device 20 to the slave device 30. Therefore, the master device 20 proceeds to step S590. On the other hand, if the value of the mapping sharing counter is a value other than zero, that is, the new channel mapping has not been shared in the master device 20 and the slave device 30, the master device 20 proceeds to step S520.

[0102] In step S520, the master device 20 sends the new channel mapping to the slave device 30. At this time, the master device 20 sends the new channel mapping together with information indicating the timing of starting to use the new channel mapping. The timing of starting to use the new channel mapping is as follows: Figure 7 As in the example shown in the timing diagram of , it arrives every time a channel mapping update cycle passes.

[0103] In step S710, the slave device 30 receives the new channel mapping and timing information sent from the master device 20. When the slave device 30 receives the new channel mapping and timing information in step S710, in step S720, a checksum determination is performed based on the error detection code included in the received data packet to confirm whether the new channel mapping and timing information is correctly received. In the case where the slave device 30 determines in step S720 that the new channel mapping and timing information is not correctly received based on the checksum determination result, for example, in step S730, a reception confirmation signal (Ack signal) of the new channel mapping is not sent. On the other hand, in the case where the slave device 30 determines in step S720 that the new channel mapping and timing information is correctly received, in step S730, a reception confirmation signal (Ack signal) of the new channel mapping is sent back to the master device 20.

[0104] In step S530, the master device 20 receives the Ack signal from the slave device 30. And, in step S540, the master device 20 performs, for example, a checksum determination based on the error detection code included in the received Ack signal to confirm whether the Ack signal is correctly received. In addition, in the case where the master device 20 fails to receive the Ack signal itself, the result of the checksum determination becomes NG. In the following step S550, the master device 20 determines whether the result of the checksum determination in step S540 is OK (success) or NG (failure). In the case where the result of the checksum determination is OK, the master device 20 proceeds to step S560. On the other hand, in the case where the result of the checksum determination is NG, the master device 20 proceeds to step S570.

[0105] In step S560, the master device 20 resets the above-mentioned mapping sharing counter to zero. In this way, the mapping sharing counter is reset to zero when it is determined that the new channel mapping and timing information are correctly received in the slave device 30 and the slave device 30 sends an Ack signal and the master device 20 correctly receives the Ack signal. Therefore, when the value of the mapping sharing counter is zero, it can be said that the sharing of the new channel mapping in the master device 20 and the slave device 30 has been successful as described above.

[0106] For example, in Figure 7 The timing diagram of , shows the following example: the slave device 30 marked as "Slave1" starts the channel mapping update cycle, and in the initial communication after the new channel mapping sharing starts (i.e., communication event = 1), the new channel mapping and timing information from the master device 20 is normally received, and then, the Ack signal sent from the slave device 30 is also normally received in the master device 20, so that the new channel mapping is shared by the master device 20 and the slave device 30. In this case, in step S560, the mapping sharing counter is reset to zero. Therefore, in the second and subsequent communications during the channel mapping update cycle (i.e., communication events = 2 to 6), the judgment result of step S510 becomes "Yes", so the new channel mapping and timing information may no longer be sent.

[0107] On the other hand, in step S570, the master device 20 determines whether to perform the process for retransmission within the same communication event because the Ack signal is not correctly received. In the case where the master device 20 determines in step S570 that retransmission is to be performed, the process from step S520 is performed again. In the case where it is determined in step S570 that retransmission is not to be performed, the master device 20 proceeds to step S580. In step S580, the master device 20 increases the mapping sharing counter by 1. In this way, the mapping sharing counter is incremented without considering that the sharing of the new channel mapping in the master device 20 and the slave device 30 has been successful. Therefore, in the case where the value of the mapping sharing counter is a value other than zero, it can be said that it indicates that the sharing of the new channel mapping in the master device 20 and the slave device 30 has not been successful.

[0108] For example, in Figure 7 The timing diagram of , shows the following example: the slave device 30 marked as "Slave2" starts the channel mapping update cycle, and in the first communication after the new channel mapping sharing starts (i.e., communication event = 1), it is considered that the sharing of the new channel mapping between the master device 20 and the slave device 30 has failed because the new channel mapping and timing information from the master device 20 cannot be received normally, the Ack signal is not sent back, or the master device 20 cannot receive the Ack signal normally although the slave device 30 sends the Ack signal. In this case, in step S580, the mapping sharing counter is increased by 1 and becomes a value other than zero. Therefore, in the second and subsequent communications during the channel mapping update cycle (i.e., communication events = 2 to 6), the judgment result of step S510 becomes "No", and the processing after step S520 is executed. That is, the sending of the new channel mapping and timing information from the master device 20 to the slave device 30 is repeatedly performed in each communication event. The sending of the new channel map and timing information continues during the channel map update period until the sharing of the channel map in the master device 20 and the slave device 30 is successful and the map sharing counter is reset to zero.

[0109] In step S590, the host device 20 determines whether the waiting time until the new channel map is updated has passed, that is, determines whether the channel map update cycle has expired. If it is determined in this determination process that the waiting time has passed, the host device 20 proceeds to step S600. On the other hand, if it is determined that the waiting time has not passed, the host device 20 ends the process. Figure 6 The process is shown in the flowchart.

[0110] In step S600, the master device 20 determines whether the value of the mapping sharing counter is zero. When the value of the mapping sharing counter is zero, the value of the mapping sharing counter indicates that the sharing of the new channel mapping in the master device 20 and the slave device 30 has been successful. Therefore, the master device 20 updates the channel mapping from the current channel mapping to the new channel mapping in step S610. As a result, the master device 20 and the slave device 30 can communicate via the communication channel selected according to the new channel mapping.

[0111] On the other hand, if it is determined in step S600 that the value of the mapping shared counter is a value other than zero, there is a possibility that, although the new channel mapping and timing information is transmitted a predetermined number of times (corresponding to the first predetermined number in the claims), Figure 7 In the example shown, six times are sent), but the sharing of the new channel mapping in the master device 20 and the slave device 30 also fails. Therefore, the master device 20 cuts off the communication connection with the slave device 30 in step S620. At this time, the communication connection cut off is the wireless communication connection with the slave device 30 that is considered to have not completed the sharing of the channel mapping among the multiple slave devices 30.

[0112] Furthermore, the timing of disconnecting the communication connection with the slave device 30 is as follows: Figure 7 As shown in the timing diagram of , the timing of starting the application period of the new channel mapping, that is, the timing of starting the use of the new channel mapping, corresponds to. Therefore, it is possible to prevent the continuous occurrence of communication errors due to the difference in channel mapping between the master device 20 and the slave device 30, thereby suppressing the occurrence of a situation where communication reliability is reduced.

[0113] When the master device 20 disconnects the communication connection with the slave device 30, the master device 20 starts the above-mentioned process in order to reconnect with the slave device 30 whose communication connection has been disconnected. Figure 4 On the other hand, when the slave device 30 cannot communicate data with the master device 20 and the number of communication errors reaches a predetermined number (a number corresponding to the third predetermined number in the claims), the communication connection with the master device 20 is cut off. After the communication connection is cut off, the slave device 30 also starts Figure 4 As a result, the master device 20 and the slave device 30 are attempted to reconnect. In the connection sequence as the process of the reconnection, a communication connection is established between the master device 20 and the slave device 30, and then the connection information including the channel mapping indicating the communication channel used for wireless communication is shared between the master device 20 and the slave device 30. As a result, the master device 20 and the slave device 30 can perform wireless communication again.

[0114] (Second Embodiment)

[0115] Next, a wireless communication system 10 according to a second embodiment of the present disclosure will be described with reference to the drawings. Since the wireless communication system 10 according to this embodiment has the same configuration as the wireless communication system 10 according to the first embodiment, description of the configuration will be omitted.

[0116] In the wireless communication system 10 of the first embodiment described above, when it is not determined that the new channel mapping is successfully shared between the master device 20 and the slave device 30 despite the transmission of the new channel mapping and timing information for a predetermined number of times in the channel mapping update cycle, the master device 20 disconnects the communication connection with the slave device 30 at the timing of starting the use of the new channel mapping. Here, in the first embodiment described above, the master device 20 determines whether the sharing of the new channel mapping between the master device 20 and the slave device 30 is successful or failed based on the failure to receive the channel mapping reception confirmation signal (Ack signal) from the slave device 30.

[0117] However, even if it is assumed that the master device 20 cannot normally receive the Ack signal from the slave device 30, there is a possibility that the slave device 30 can normally receive the new channel mapping and timing information sent from the master device 20. In the case where the slave device 30 can normally receive the new channel mapping and timing information, the master device 20 and the slave device 30 can communicate using the new channel mapping. Therefore, if the slave device 30 can receive the new channel mapping and timing information, it is not necessary to cut off the communication connection with the slave device 30 based on the fact that the master device 20 cannot normally receive the Ack signal from the slave device 30. Furthermore, if the communication connection with the slave device 30 is cut off, the master device 20 and the slave device 30 will not be able to communicate data during the period required for reconnection.

[0118] Therefore, in the wireless communication system 10 of the present embodiment, in order to prevent useless disconnection of the communication connection, the master device 20 disconnects the communication connection with the slave device 30 based on confirming that the sharing of the new channel mapping is not achieved between the master device 20 and the slave device 30, not only based on the situation that the Ack signal cannot be received normally.

[0119] Hereinafter, the wireless communication system 10 of the present disclosure will be described mainly focusing on the points that are different from the wireless communication system 10 of the first embodiment.

[0120] Figure 8 : is a flowchart showing the channel mapping sharing process executed in the wireless communication system 10 according to the present embodiment. Figure 8 The channel mapping sharing process of the second embodiment shown in the flowchart is relative to Figure 6 For the channel mapping sharing process of the first embodiment shown in the flowchart of FIG, the processes of step S600 and step S620 are deleted. Figure 8 The channel mapping sharing process shown in the flowchart and Figure 6 There is no difference in the channel mapping sharing process shown in the flowchart.

[0121] Figure 8 Since the channel mapping sharing process shown in the flowchart deletes the processing of steps S600 and S620, when the main device 20 determines in step S590 that the waiting time until updating to the new channel mapping has passed, it does not determine whether the sharing of the new channel mapping based on the normal reception of the Ack signal is successful, but must update the channel mapping from the current channel mapping to the new channel mapping in step S610.

[0122] And, if Fig. 9 As shown in the timing diagram of , the master device 20 attempts data communication with the slave device 30 a predetermined number of times (equivalent to the second predetermined number in the claims) via the communication channel selected according to the updated new channel mapping. Fig. 9 In the example shown in the timing diagram of , the prescribed number of times is set to one, but is not limited to one, and may be two or more. However, the prescribed number of times corresponding to the second prescribed number of times is set to a number less than the prescribed number of times corresponding to the third prescribed number of times, wherein the third prescribed number of times is used to determine the disconnection of the communication connection when the sharing of the channel mapping is not failed but the communication error continues.

[0123] If the master device 20 is able to communicate with the slave device 30 during the predetermined number of communication attempts with the slave device 30, it is considered that the new channel mapping has been successfully shared between the master device 20 and the slave device 30. Therefore, the master device 20 continues to communicate with the slave device 30 using the new channel mapping as it is.

[0124] On the other hand, if the master device 20 cannot communicate with the slave device 30 during the predetermined number of communication attempts with the slave device 30, it is considered that the sharing of the new channel mapping between the master device 20 and the slave device 30 has failed. In this case, the master device 20 cuts off the communication connection with the slave device 30 when it is determined that the master device 20 cannot communicate with the slave device 30 even after the predetermined number of communication attempts. Fig. 9 In the example shown in the timing diagram, the master device 20 attempted to communicate with the slave device 30 represented as "Slave2" via the communication channel selected according to the new channel mapping, but because it was impossible to communicate with the slave device 30 of "Slave2", the communication connection with the slave device 30 of "Slave2" was cut off when the initial communication event ended.

[0125] In order to disconnect the communication connection at the above timing, the wireless communication system 10 of the second embodiment performs the following operations while using the new channel mapping. Fig.10 The flow chart shows the communication sequence. Fig.10 The communication sequence shown in the flowchart is relative to Figure 5 With respect to the communication sequence of the first embodiment shown in the flowchart of FIG. 1 , the processes of steps S232 , S242 , S244 , and S246 are added.

[0126] exist Fig.10 In the flowchart of FIG. 2, in step S232, it is determined whether the checksum determination is OK or NG based on the checksum determination result in step S230. If the checksum determination is OK, it can be considered that the master device 20 and the slave device can normally perform data requests and send and receive data in response to the data requests in the processing of steps S210 and S310 using the new channel mapping and the processing of steps S220 and S330. Therefore, if it is determined in step S232 that the checksum determination is OK, the master device 20 proceeds to step S250 and continues to communicate with the slave device 30 using the new channel mapping.

[0127] On the other hand, if the checksum is determined to be NG in step S232, the main device 20 proceeds to step S240. In step S240, as in the first embodiment, it is determined whether to perform a process for retransmission within the same communication event. If the main device 20 determines in step S240 that retransmission is to be performed, the process from step S210 is performed again. If it is determined in step S240 that retransmission is not to be performed, the main device 20 proceeds to step S242.

[0128] In step S242, the master device 20 determines whether the master device 20 and the slave device 30 have successfully shared the new channel mapping in the channel mapping update period immediately before. More specifically, the master device 20 determines whether the master device 20 and the slave device 30 have successfully shared the new channel mapping in the channel mapping update period immediately before the channel mapping update period in which the new channel mapping is applied is about to start. Figure 8The value of the mapping sharing counter in the flowchart is used to determine whether the new channel mapping is successfully shared in the channel mapping update cycle just before, and the determination result is saved. In addition, the master device 20 determines whether the sharing of the new channel mapping is successful based on the saved determination result in step S242. If it is determined that the new channel mapping is successfully shared in the channel mapping update cycle just before, the master device 20 enters the processing of step S250 and continues to communicate with the slave device 30. However, if the master device 20 cannot normally implement data communication for a continuous predetermined number of times (equivalent to the third predetermined number of times in the claims), the communication connection is cut off. On the other hand, if it is determined that the new channel mapping is not successfully shared in the channel mapping update cycle just before, the master device 20 enters step S244. In step S244, after the channel mapping is updated to the new channel mapping, it is determined whether the communication with the slave device 30 has failed for a predetermined number of times (equivalent to the second predetermined number of times in the claims). At this time, if it is determined that the communication with the slave device 30 has failed for a predetermined number of times, the master device 20 enters step S246. In step S246 , the master device 20 disconnects the communication connection with the slave device 30 .

[0129] In addition, it is also possible to configure that if communication with the slave device 30 succeeds even once after updating to the new channel mapping, the processing of steps S242, S244, and S246 is skipped thereafter. Alternatively, it is also possible to configure that even if the channel mappings of the master device 20 and the slave device 30 are different, there is a possibility that communication succeeds by chance, and therefore, the processing of steps S242, S244, and S246 is executed regardless of whether the communication succeeds once.

[0130] As mentioned above, although the preferred embodiment of the present disclosure has been described, the present disclosure is not limited to the above-mentioned embodiment at all, and can be implemented with various modifications within the scope not departing from the gist of the present disclosure.

[0131] For example, in the above-described embodiments, when the master device 20 and the slave device 30 fail to share the channel mapping, the master device 20 sends the channel mapping to the slave device 30 in all communication events (communication events = 1 to 6) of the channel mapping update period.

[0132] However, in the channel map update cycle, the upper limit number of times the channel map is sent from the master device 20 to the slave device 30 (equivalent to the first specified number in the claims) may be set to be less than the scheduled number of communications between the master device 20 and the slave device 30 from the start of sharing the channel map until the start of using the channel map, that is, the number of communication events included in the channel map update cycle. Furthermore, in the case where the sharing of the channel map is not determined to be successful even though the number of times the channel map is sent from the master device 20 to the slave device 30 reaches the upper limit number (the first specified number), the master device 20 may cut off the communication connection with the slave device 30 at the timing determined in this way (equivalent to the third timing in the claims).

[0133] For example, in Fig.11 In the example shown in the timing diagram of , the master device 20 disconnects the communication connection with the slave device 30 at the time when it is determined that the sharing of the channel mapping has failed five times, which is less than the number of communication events (six) during the channel mapping update period. In the case where the sharing of the new channel mapping is not successful, the possibility of successful communication between the master device 20 and the slave device 30 is low during the application period (the next channel mapping update period) of the application of the new channel mapping. Therefore, in this modification, for example, the communication connection is disconnected at an earlier time than the operation of waiting for the start of the next channel mapping update period to disconnect the communication connection. Thus, it is possible to achieve early reconnection between the master device 20 and the slave device 30. As a result, it is possible to shorten the period of interruption of communication between the master device 20 and the slave device 30 due to the inconsistency of the channel mapping. Thus, for example, when at least one of the master device 20 and the slave device 30 is mounted on a vehicle, it is possible to shorten the period of important communication in the vehicle, such as communication for notifying an abnormality of an onboard device and communication for instructing important control in the onboard device, between the master device 20 and the slave device 30. The upper limit number may be set to a number less than the number of communication errors in data communication for the master device 20 to cut off the communication connection with the slave device 30 (a number corresponding to the third predetermined number in the claims).

[0134] In the second embodiment described above, the number of times the channel map is re-sent may be less than the number of communication events included in the channel map update period, and in the communication event in which the channel map is not sent, the master device 20 performs other processing (for example, the creation of the next new channel map for the slave device 30 that maintains the communication connection, etc.). Fig. 9 In the example shown in the timing diagram of , in the sixth communication event, the channel mapping to "Slave2" is not retransmitted, and the master device 20 can also perform other processing in the sixth communication event. Thus, the processing resources of the master device 20 can be allocated to other processing.

[0135] Finally, this specification discloses the following multiple technical concepts and their multiple combinations. The following multiple technical concepts are suitable not only for the wireless communication system 10, but also for the wireless communication method and the wireless communication program.

[0136] (Technical Thought 1)

[0137] The wireless communication system is a system in which a master device performs wireless communication with a slave device via a communication channel sequentially selected from a plurality of communication channels, wherein

[0138] A wireless communication system comprising at least one of (i) a circuit and (ii) a processor having a memory storing a computer program code,

[0139] At least one of a circuit and a processor with a memory enables the wireless communication system to implement:

[0140] a quality determination unit for determining the communication quality of each communication channel when the master device and the slave device are performing wireless communication;

[0141] a communication channel determination unit that determines a communication channel used for wireless communication based on a determination result of the communication quality of each communication channel by the quality determination unit;

[0142] a channel map sharing unit that transmits a channel map indicating the communication channel determined by the communication channel determination unit from the master device to the slave device so that the master device and the slave device share the channel map;

[0143] a sharing determination unit that determines whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; and

[0144] a communication disconnection unit configured to disconnect the communication connection with the slave device in the master device,

[0145] The channel map sharing unit repeatedly transmits the channel map when the sharing determination unit does not determine that sharing of the channel map is achieved despite the transmission of the channel map,

[0146] The communication disconnection unit disconnects the communication connection with the slave device at a predetermined timing based on the fact that the sharing determination unit has never determined that the channel map has been shared even though the channel map sharing unit has sent the channel map a first predetermined number of times.

[0147] (Technical Thought 2)

[0148] The wireless communication system according to technical idea 2, wherein the channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map,

[0149] The predetermined timing corresponds to a first timing for starting utilization of the channel mapping.

[0150] (Technical Thought 3)

[0151] The wireless communication system according to technical idea 1, wherein the channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map,

[0152] The specified timing corresponds to a second timing for determining the following situation: in the master device, at the timing of starting to use the channel mapping, communication with the slave device is performed using the communication channel selected according to the channel mapping sent to the slave device, and even if the communication is attempted a second specified number of times, communication with the slave device cannot be performed.

[0153] (Technical Thought 4)

[0154] According to the wireless communication system of technical idea 3, when the master device successfully communicates with the slave device through communication attempts within the second specified number of times, the master device continues to communicate via the communication channels selected in sequence according to the channel mapping sent to the slave device.

[0155] (Technical Thought 5)

[0156] A wireless communication system according to technical idea 3 or 4, wherein, when the sharing determination unit determines that the channel mapping has been shared, in the master device, at the timing of starting to use the channel mapping, communication with the slave device is performed via the communication channels selected in sequence according to the channel mapping sent to the slave device, and when communication with the slave device has not been achieved even after a third prescribed number of times greater than the second prescribed number of times has been performed on the slave device, the communication disconnection unit disconnects the communication connection with the slave device.

[0157] (Technical Thought 6)

[0158] The wireless communication system according to technical idea 1, wherein the channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map,

[0159] The first predetermined number of times is set to be less than a predetermined number of times of communication between the master device and the slave device until the use of the channel mapping starts,

[0160] The predetermined timing corresponds to a third timing at which it is determined that, although the channel map sharing unit has transmitted the channel map a number of times reaching the first predetermined number of times, the sharing determination unit has never determined that the channel map has been shared.

[0161] (Technical Thought 7)

[0162] A wireless communication system according to any one of technical ideas 1 to 6, wherein, if the communication disconnection unit disconnects the communication connection with the slave device, the master device attempts to reconnect the wireless communication with the slave device, and in the process of reconnection, the communication channel information used for wireless communication is shared between the master device and the slave device.

[0163] (Technical Thought 8)

[0164] According to any one of technical concepts 1 to 7, the wireless communication system, wherein the master device communicates with a plurality of the slave devices at the same time,

[0165] The communication disconnection unit disconnects the wireless communication with the slave device considered to have failed to share the channel map among the plurality of slave devices at the predetermined timing.

[0166] (Technical Thought 9)

[0167] A wireless communication system according to any one of technical concepts 1 to 8, wherein the communication channel determination unit periodically updates the communication channels used for wireless communication based on the determination result of the communication quality of each communication channel by the quality determination unit,

[0168] The channel map sharing unit periodically transmits an updated channel map indicating updated communication channels from the master device to the slave device, so that the master device and the slave device share the updated channel map.

[0169] In this disclosure, the term "processor" is a single or multiple hardware processors configured to execute program code (i.e., one or more instructions of a program). In other words, a "processor" is one or more programmable hardware devices. For example, a "processor" is a general-purpose or special-purpose processor, which can be a CPU, a microprocessor, and a PLD such as an FPGA, but is not limited thereto.

[0170] In the present disclosure, the term "memory" refers to one or more hardware memories configured to record computer program code and / or data in a manner that can be accessed by a processor. "Memory" can be implemented by memory technologies such as SRAM, SDRAM, non-volatile / flash memory, or other types of memory. Computer program code is recorded on the memory and can be executed by the processor to enable the processor to implement the various functions described above.

[0171] In this disclosure, the term "circuit" refers to a single or multiple hardware logic circuits configured to implement the aforementioned functions. In other words (and in contrast to "processor"), a "circuit" refers to one or more non-programmable circuits. For example, a "circuit" can be an IC such as an ASIC or other type of non-programmable circuit.

[0172] In the present disclosure, the expression "at least one of the circuit and the processor" should be interpreted as a disjunction (logical OR) and should not be interpreted as at least one circuit and at least one processor. Therefore, in the present disclosure, the expression "at least one of the circuit and the processor enables the wireless communication system to perform functions" should be understood as: (i) only the circuit enables the wireless communication system to perform all functions; (ii) only the processor enables the wireless communication system to perform all functions; or (iii) the circuit enables the wireless communication system to perform a part of the functions and the processor enables the wireless communication system to perform the remaining functions. For example, in the case of (iii) above, functions A and B among all functions A to C can be implemented by the circuit and the remaining function C can be implemented by the processor.

[0173] The control unit and method described in the present disclosure can be implemented by a special-purpose computer, which is provided by constituting a processor and a memory programmed in a manner to execute one or more functions embodied by a computer program. Alternatively, the control unit and method described in the present disclosure can also be implemented by a special-purpose computer, which is provided by constituting a processor using one or more special-purpose hardware logic circuits. Alternatively, the control unit and method described in the present disclosure can also be implemented by one or more special-purpose computers consisting of the following combination, which refers to a combination of a processor and a memory programmed in a manner to execute one or more functions and a processor consisting of one or more hardware logic circuits. In addition, the computer program can also be stored as an instruction executed by a computer in a non-temporary tangible storage medium that can be read by the computer.

[0174] Here, the flowchart or the processing of the flowchart recorded in this application is composed of multiple sections (or steps), and each section is expressed as S10, for example. Furthermore, each section can be divided into multiple sub-sections, and on the other hand, multiple sections can also be combined into one section. Furthermore, each section thus constructed can be referred to as a device, a module, or a means.

[0175] The present disclosure is described based on the embodiments, but it should be understood that the present disclosure is not limited to these embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms in which only one element, more than one element, or less than one element are included, also fall within the scope and thought of the present disclosure.

Claims

1. A wireless communication system, wherein a master device performs wireless communication with a slave device via a communication channel selected sequentially from a plurality of communication channels, characterized in that: The wireless communication system comprises: a quality determination unit for determining the communication quality of each communication channel when the master device and the slave device are performing wireless communication; a communication channel determination unit that determines a communication channel used for wireless communication based on a determination result of the communication quality of each communication channel by the quality determination unit; a channel map sharing unit that transmits a channel map indicating the communication channel determined by the communication channel determination unit from the master device to the slave device so that the master device and the slave device share the channel map; a sharing determination unit that determines whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; as well as a communication disconnection unit configured to disconnect the communication connection with the slave device in the master device, The channel map sharing unit repeatedly transmits the channel map when the sharing determination unit does not determine that sharing of the channel map is achieved despite the transmission of the channel map, The communication disconnection unit disconnects the communication connection with the slave device at a predetermined timing based on the fact that the sharing determination unit has never determined that the channel map has been shared even though the channel map sharing unit has sent the channel map a first predetermined number of times.

2. The wireless communication system according to claim 1, characterized in that: The channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map. The predetermined timing corresponds to a first timing for starting utilization of the channel mapping.

3. The wireless communication system according to claim 1, characterized in that: The channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map. The specified timing corresponds to a second timing for determining the following situation: in the master device, at the timing of starting to use the channel mapping, communication with the slave device is performed using the communication channel selected according to the channel mapping sent to the slave device, and even if the communication is attempted a second specified number of times, communication with the slave device cannot be performed.

4. The wireless communication system according to claim 3, characterized in that: When the master device successfully communicates with the slave device through the communication attempts within the second predetermined number of times, the master device continues the communication via the communication channels sequentially selected according to the channel map transmitted to the slave device.

5. The wireless communication system according to claim 3, characterized in that: When it is determined in the sharing determination unit that the channel mapping has been shared, in the master device, at the timing of starting to use the channel mapping, communication with the slave device is performed via the communication channels selected in sequence according to the channel mapping sent to the slave device, and when communication with the slave device has not been achieved even after a third prescribed number of times greater than the second prescribed number of times has been performed with the slave device, the communication disconnection unit disconnects the communication connection with the slave device.

6. The wireless communication system according to claim 1, characterized in that: The channel map sharing unit transmits the channel map together with information indicating a timing to start using the channel map. The first predetermined number of times is set to be less than a predetermined number of times of communication between the master device and the slave device until the use of the channel mapping starts, The predetermined timing corresponds to a third timing at which it is determined that, although the channel map sharing unit has transmitted the channel map a number of times reaching the first predetermined number of times, the sharing determination unit has never determined that the channel map has been shared.

7. The wireless communication system according to any one of claims 1 to 6, characterized in that: When the communication disconnection unit disconnects the communication connection with the slave device, the master device attempts to reconnect the wireless communication with the slave device. During the reconnection process, communication channel information used for wireless communication is shared between the master device and the slave device.

8. The wireless communication system according to any one of claims 1 to 6, characterized in that: The master device communicates with a plurality of the slave devices at the same time, The communication disconnection unit disconnects the wireless communication with the slave device considered to have failed to share the channel map among the plurality of slave devices at the predetermined timing.

9. The wireless communication system according to any one of claims 1 to 6, characterized in that: The communication channel determination unit periodically updates the communication channel used for wireless communication based on the determination result of the communication quality of each communication channel by the quality determination unit. The channel map sharing unit periodically transmits an updated channel map indicating updated communication channels from the master device to the slave device, so that the master device and the slave device share the updated channel map.

10. A wireless communication method, which is a method in which a master device performs wireless communication with a slave device via a communication channel selected sequentially from a plurality of communication channels, characterized in that: The wireless communication method comprises: a quality determination step of determining the communication quality of each communication channel when the master device and the slave device are performing wireless communication; a communication channel determining step of determining a communication channel used for wireless communication based on the determination result of the communication quality of each communication channel in the quality determination step; a channel map sharing step of transmitting a channel map indicating the communication channel determined in the communication channel determination step from the master device to the slave device so that the master device and the slave device share the channel map; a sharing determination step of determining whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; and a communication disconnection step of disconnecting the communication connection with the slave device in the master device, In the channel map sharing step, when the channel map is transmitted but it is not determined in the sharing determination step that the sharing of the channel map is achieved, the transmission of the channel map is repeated, Based on the fact that although the channel mapping has been sent a first specified number of times in the channel mapping sharing step, no determination is made in the sharing determination step that the channel mapping has been shared, the communication connection with the slave device is disconnected at a specified timing in the communication disconnection step.

11. A persistent computer readable medium having instructions to be executed by at least one processor, characterized in that: The command is used for the master device to perform wireless communication with the slave device via a communication channel selected sequentially from a plurality of communication channels, and when executing the command, at least one of the processors implements: a quality determination function for determining the communication quality of each communication channel when the master device and the slave device are in wireless communication; a communication channel determination function for determining a communication channel to be used for wireless communication based on a determination result of the communication quality of each communication channel obtained by the quality determination function; a channel map sharing function for transmitting a channel map representing a communication channel determined by the communication channel determination function from the master device to the slave device so that the master device and the slave device share the channel map; a sharing determination function for determining whether the channel map has been shared by the master device and the slave device based on a reception result of a channel map reception confirmation signal transmitted from the slave device in response to receiving the channel map; as well as a communication disconnection function for disconnecting the communication connection with the slave device in the master device, When the channel map is transmitted by the channel map sharing function but the sharing determination function does not determine that the sharing of the channel map is achieved, the transmission of the channel map is repeated, Based on the fact that although the channel mapping sharing function has sent the channel mapping a first specified number of times but the sharing determination function has never determined that the channel mapping has been shared, the communication disconnection function disconnects the communication connection with the slave device at a specified timing.

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